Battles & Wars › World War II › Manhattan Project
Los Alamos Laboratory
founded 1943; Trinity test July 16, 1945· Arms maker, factory or program· Arms makers & war industry
Well documentedSolid records, physical evidence or scientific consensus.
The secret New Mexico laboratory where scientists under J. Robert Oppenheimer designed and built the first atomic bombs.
See it on the Battles & Wars map →What happened
In late 1942 General Leslie Groves and Oppenheimer chose a remote boys' ranch school on a mesa near Santa Fe. The lab opened in 1943 and drew scientists such as Enrico Fermi, Hans Bethe and Richard Feynman. It designed two bombs: a simpler uranium 'gun' type and a complex plutonium 'implosion' type, which squeezed a plutonium core with explosives. The implosion design was tested at Trinity on July 16, 1945. Soviet spies, including Klaus Fuchs, passed secrets to Moscow.
Why it matters
It turned atomic physics into usable weapons, and as Los Alamos National Laboratory it still designs and maintains US nuclear warheads.
How we know
Declassified lab records, the 1945 Smyth Report, Oppenheimer's 1954 security hearing transcript, and histories such as 'American Prometheus' (2005), basis of the 2023 film 'Oppenheimer.'
Still debated
How far fallout from the Trinity test harmed New Mexico residents, who were never warned, is still disputed; they were long excluded from federal compensation.
Connections (3)
▸Los Alamos Laboratory designed the two bombs used in the Atomic bombings of Hiroshima and NagasakiWell documented
The connection
Los Alamos designed both bombs. 'Little Boy' fired one piece of uranium into another inside a gun barrel and was considered so certain to work that it was never tested. 'Fat Man' used explosives to crush a plutonium core, a design proved at Trinity. Lab teams assembled both on Tinian.
When and how
Los Alamos, New Mexico, 1943–45; Trinity site, July 16, 1945; Tinian, August 1945; Oppenheimer's scientists and Project Alberta assembly teams.
How we know
Declassified design and assembly records, Project Alberta reports, and participants' memoirs.
Debates and open questions
Some project scientists, in Chicago's 1945 Franck Report, urged a demonstration on an empty area first; Oppenheimer's advisory panel saw no workable demonstration. Whether one could have worked is still debated.
▸Los Alamos Laboratory designed the first Hydrogen bombWell documented
The connection
At Los Alamos in early 1951, mathematician Stanislaw Ulam and physicist Edward Teller worked out how an atomic explosion's radiation could compress fusion fuel. Lab scientists, with Richard Garwin drafting the engineering design, built the 82-ton Ivy Mike device, tested in 1952. A rival lab, Livermore, was founded that year.
When and how
Los Alamos, New Mexico, 1950–52; the Teller–Ulam report of March 1951; the test at Enewetak Atoll, November 1, 1952.
How we know
Declassified Los Alamos reports, Garwin's later disclosed role, and histories such as Richard Rhodes's 'Dark Sun' document the work.
Debates and open questions
How much credit belongs to Teller versus Ulam is still argued; Teller often played down Ulam's role.
▸Oak Ridge (Clinton Engineer Works) shipped enriched uranium to Los Alamos LaboratoryWell documented
The connection
Enriched uranium from Oak Ridge was shipped to Los Alamos, where scientists measured it and machined it into bomb parts. By July 1945 there was enough highly enriched uranium for only one bomb, Little Boy, one reason the uranium design went untested.
When and how
Oak Ridge, Tennessee, to Los Alamos, New Mexico, 1944–1945, carried under guard by Army couriers.
How we know
Shipment and accountability records in declassified Manhattan District files.
Debates and open questions
How soon a second uranium bomb could have been ready is debated, and the exact delivery schedule is partly reconstructed from scattered records.